Electronic apparatuses in the fields of video, audio and air-conditioning have recently had various high-end functions, so that switches and remote controllers that operate these apparatuses are required to operate reliably with a good operational feel.
FIGS. 8 and 9 are a sectional view and an exploded perspective view of conventional remote controller 5001, respectively. Case 1 has substantially a box shape and is made of insulating resin. Operating unit 2 is made of insulating resin. Plural holes 1A are formed in a top surface of case 1. Operating unit 2 is inserted movably up and down in each of holes 1A, and includes operating section 2A projecting upward from hole 1A.
Guide wall 1B having a squared tubular shape protrudes downward from an inner edge of hole 1A. Operating unit 2 includes depressing section 2B protruding downward from a lower surface thereof. Guide wall 1B is spaced apart by a small gap from a side surface of operating unit 2.
Plural wiring patterns are provided on an upper surface and a lower surface of wiring board 3. Fixed contacts 4A and 4B made of conductive material, such as carbon, are provided on the upper surface of wiring board 3. Movable contact 5 which is made of conductive metal plate and which has a substantially dome shape is placed on fixed contact 4B. Movable contact 5 faces fixed contact 4B with a predetermined gap between contacts 4B and 5.
Elastic sheet 6 made of elastic insulator, such as rubber, is provided on the upper surface of wiring board 3. Elastic sheet 6 has thinner portion 6A over movable contact 5. A projection is provided on a lower surface of thin portion 6A, thus providing a switch.
Transmitting section 7 and control section 8 are provided on the upper surface and the lower surface of wiring board 3. Transmitting section 7 includes an electronic component, such as a light emitting diode, for transmitting a remote controlling signal. Control section 8 includes a semiconductor device, such as a microprocessor, and is coupled to transmitting section 7 and fixed contacts 4A and 4B via the wiring patterns.
Cover 9 which has a box shape and which is made of insulating resin covers a lower surface of case 1 accommodating operating unit 2 and wiring board 3 therein. Cover 9 is fixed to case 1 with fixing members, such as screws, thus providing remote controller 5001.
Remote controller 5001 is directed toward an electronic apparatus, such as a television receiver or a radio receiver, and operating section 2A of operating unit 2 is configured to be depressed. When operating section 2A is depressed, depressing section 2B depresses movable contact 5 via thin portion 6A of elastic sheet 6. Movable contact 5 accordingly deforms elastically so as to turn inside out and contact fixed contact 4A, thereby electrically connecting fixed contact 4A to fixed contact 4B. Upon fixed contact 4A being connected electrically to fixed contact 4B, control section 8 allows transmitting section 7 to transmit an infrared remote controlling signal to the electronic apparatus in order to remotely control the electronic apparatus, for example, to turn on and off the apparatus, to select a channel, and to increase and decrease sound volume.
Guide wall 1B provided at the inner edge of hole 1A is spaced by a small clearance from the side surface of operating unit 2. Guide wall 1 allows operating unit 2 to be depressed while operating unit 2 slants little or wobbles little. That is, the entire inner wall of guide wall 1B has a length substantially identical to that of the side surface of operating unit 2A, and guides the entire side surface of operating unit 2 so as to prevent operating unit 2 from slanting and wobbling during the operation of operating unit 2. This prevents operating unit 2 from sinking in case 1 even when receiving a large force, thereby allowing the operating unit to be pressed reliably.
In conventional remote controller 5001, operating unit 2 is guided by guide wall 1B surrounding operating unit 2 across the small gap and having a large length. When a liquid or drink, such as coffee or juice, is spilled onto to the upper surface of operating unit 2 or case 1, the liquid may flow through hole 1A, then dry and clot in the small gap. In this case, the clot prevents operating unit 2 from moving up and down, decreases the good feeling, and prevents operating unit 2 from moving smoothly, thus preventing remote controller 5001 from operating.